[alsa-devel] [PATCH 1/7] ASoC: Intel: Skylake: Add Resume capability in PCM info.

[Takashi Iwai]

On Tue, 24 Nov 2015 03:44:49 +0100,
Vinod Koul wrote:
> 
> On Mon, Nov 23, 2015 at 07:45:20PM +0100, Takashi Iwai wrote:
> > On Mon, 23 Nov 2015 17:56:23 +0100,
> > Vinod Koul wrote:
> > > 
> > > From: Jeeja KP <jeeja.kp at intel.com>
> > > 
> > > This patch adds pcm capability to support Resume.
> > 
> > The flag indicates that the driver is capable of the full resume --
> > i.e. it must resume everything at the exactly same point to be
> > suspended.  Is it really the case?
> > 
> > If it's not and it's instead a kind of restart of streams, don't add
> > this flag.  The lack of the flag doesn't mean that the driver can't
> > resume at all.
> 
> Yes, with this patch series we are able to resume from previous position.

I suppose you tested hibernation, too?
How does it assure that the in-flight data on FIFO are restored after
the link reset and re-prepare?

> Here is my test:
> 
> # aplay -Dhw:0,0 play.wav
> Playing WAVE 'play.wav' : Signed 16 bit Little Endian, Rate 48000 Hz,
> Stereo
> Suspended. Trying resume. Done.

As mentioned, the resume usually works (sort of), even without
SNDRV_PCM_INFO_RESUME bit.  It's because alsa-lib tries to re-prepare
the stuff by itself.

Did you try only the patch 2 without this patch?


Takashi